The present invention relates generally to the timber products industry, and particularly to methods and apparatus for the separation of bast fibers. Fibers and other materials from plants such as kenaf, flax, hemp, sisal, jute, ramie, bamboo, and even banana and cotton stalks, can be successfully used to create a wide range of products. These alternative plants are commonly referred to as “bast plants,” or dicotyledonous plants, which are flowering plants with net-veined leaves.
Bast plants are comprised of two primary fibrous elements: the outer fiber, similar to bark or skin, referred to as “bast,” and the inner fiber, referred to as “core.” Both of these elements can be used for different and varying purposes, and to create a wide range of products. The core from the bast plants may be used to make paper, polyesters and other fabrics, or to create reconstituted or reconsolidated paneling and wood products, or it can even be burned as fuel. The bast of the bast plants may be used to make rope, yarn, or burlap, or to manufacture lightweight and burnable materials, preferably including car parts such as dashboards, door panels, seat linings and seat backs.
Bast plants are preferable for use for many reasons. First, as mentioned, the bast and core can both be used to create a variety of different products. Second, many bast plants have phenomenal growth rates, typically reaching a harvestable height of 12-18 feet in approximately 150 growing days, whereas other organic materials such as pine or other timber generally cannot be harvested for 7-40 years. Because bast plants grow so quickly, they are a vastly renewable resource. Also, bast plants typically contain low amounts of lignin, which is the resin that binds cellulose fibers in plants and trees together. Lower amounts of lignin makes it easier to separate the core during processing, and makes it easier to further process the core at a later time as compared to other organic materials. Additionally, bast plants characteristically yield 3-5 times more usable material per acre than pine and other timbers. Bast and core are also very lightweight, thus making them easier to transport and store as compared to heavier fibers and timber.
However, current manufacturing processes are unequipped to effectively process bast plants. The bast and core are both useful for different purposes and to create different products, but the compositions of the bast and core are such that the two components must be separated from each other to be processed effectively and efficiently. Also, this separation must be accomplished without damaging or altering the biological makeup of either component.
An inherent property of a bast plant is that the bast is extremely difficult to separate from the core. Most previous processes separated the bast from the core by a human labor process called “retting,” which essentially involves soaking the bast plant for a long period of time and then hand-peeling or chopping the bast off of the core of the plant. This retting process is not only tedious and time consuming, but also inefficient as it prevents large amounts of bast fiber from being processed quickly and effectively because each bast plant must be individually peeled. Because of this long felt, but unresolved problem, industry has previously avoided the widespread use of bast plants.
Therefore, it is an aim of the present invention to provide a method and apparatus that effectively and efficiently separates bast fibers.